1. Field of the Invention
The present invention relates to a unit housing for a motor unit.
2. Discussion of the Background
One known unit housing for a motor unit includes a substantially cylindrical housing body, which contains a ring-shaped stator and a rotor, and an end housing which is butted and coupled to an end of the housing body and which covers the end of the housing body along with peripheral components, such as a sensor (see, for example, Japanese Unexamined Patent Application Publication No. 2009-284660).
In the unit housing disclosed in Japanese Unexamined Patent Application Publication No. 2009-284660, the end housing has a peripheral wall coupled to the housing body, and an end wall extending in an axially continuous form from the peripheral wall. A terminal holding block for connecting 3-phase power lines led in from the outside of the end housing and 3-phase lead wires on the stator side, respectively, is mounted to a part of an upper region of the end housing. Although the terminal holding block is in itself made of an insulating material, e.g., a resin, electroconductive bus bars and conducting terminals are disposed in a part of the terminal holding block.
The terminal holding block includes a cylindrical holder portion corresponding to each phase, and the conducting terminal is disposed within the holder portion. Further, the terminal holding block is fixedly mounted to an outer surface of the end wall in such a state that three holder portions are inserted from the outer side to the inner side of the end wall of the end housing. Three bus bars connected respectively to 3-phase cables on the PDU (Power Drive Unit) side are attached to the terminal holding block, and each bus bar is connected to the corresponding conducting terminal within the holder portion. A cutout for wire connection is provided in each holder portion of the terminal holding block. A motor terminal (i.e., a terminal of the lead wire on the stator side) is inserted into each holder portion from the distal end side thereof and is overlaid on an upper surface of the corresponding conducting terminal. The motor terminal is fastened to the corresponding conducting terminal by using a bolt that is inserted and tightened through the cutout.
Further, in the peripheral wall of the end housing at a position facing the cutout in each holder portion, there are formed a working hole through which the bolt is tightened and a recess to secure an insulating space with respect to a head of the bolt inside the holder portion. The motor terminal and the conducting terminal inside the holder portion for each phase are fastened together by using the bolt that is tightened through the working hole from the outside of the peripheral wall of the end housing. Because the end housing is made of a metal material such as an aluminum alloy, a possibility of short-circuiting is increased if the distance between the end housing and the bolt exposed from the cutout in each holder portion is too short. However, the insulating space is secured with the presence of the recess formed in the peripheral wall of the end housing, whereby a risk of short-circuiting is avoided.